a) Technical Field
The invention is directed to an integral fan and low pressure rotor for a turbofan gas turbine engine and an associated engine support ring structure that integrates the fan case, intermediate case, and core engine shaft support with radially spanning bypass stator blades and core stator blades.
b) Background of the Art
The intake section of conventional turbofan gas turbine engine includes progressively downstream as follows: a fan rotor housed within a fan case; an intermediate case with flow splitter separating the air flow into a bypass duct and a core duct; stator blades or columns within the core duct and bypass duct for structural support; and for redirecting the air flow appropriately; within the core duct a low pressure compressor blade; and thereafter further core duct stator blades and high pressure compressor rotors.
The complexity of design manufacture and maintenance of the intake section is the focus of the present invention. Manufacture of all blades and rotors require high precision machining operations and involve significant expense. The accurate assembly of numerous components together and maintenance of appropriate clearances is extremely important. In general, if any components can be eliminated or simplified the overall cost of the engine is significantly effected. Especially in the case of small engines, with diameter approximately two to three feet maximum, conventional designs require extremely accurate machining of relatively small components and assembly of these components together with minimal clearance and leakage.
As well, due to relatively low temperatures and pressure in the intake area, the stator blades are prone to accumulate ice and must be heated or otherwise deiced for safe operation, further increasing costs.
It is a object of the invention to rationalize the many complex components of the turbofan intake area reducing the complexity and number of components to achieve savings in manufacturing and maintenance costs.
It is a further object of the invention to enhance the structural integrity of the intake area to replace conventional built up structural supports comprised of many interconnected members with a single integrally cast engine support ring.